Fire rated glass is used in fire separations in a building. These separations are required under the relevant building code. These separations have different requirements depending on the kind of building and the type of occupancy the building will have.
Some fire rated glass is used in locations to provide smoke and flame control. This means to slow the passage of smoke and flame through a building should there be a fire. This is absolutely critical as most of the deaths in building fires historically happened from smoke inhalation or smoke blocking the path of egress. Smoke and flame control is the initial and critical first stage of protecting the building and its occupants in a fire.
There are also fire-protective applications for fire rated glass. Fire-protective applications are more serious than simple smoke control and includes both glass and other materials. Most building codes permit fire-protective materials to be used in certain locations under certain limits. For fire-protective glass this usually means that there can be a fire-rated glass in a fire-rated door. Sidelites and borrowed lites are also allowed in fire-protective situations up to certain limits.
The highest level of fire rated glazing belongs to the fire-resistive class of products. Fire-resistive products have even higher levels of performance than the others. In general they are not defined as glass or windows, but rather as fire-rated materials alongside drywall and concrete. In this sense they pass the same stringent tests required for complete fire walls. They are very useful to architects who want to avoid the use of boring drywall or concrete fire walls and instead prefers the openess of glass. Fire-resistive glass essentially is an upgrade/replacement for other opaque fire-resistive materials. No longer are architects limited to lining their fire stairwells with concrete – they can now use beautiful fire-resistive glass.
The building codes define the locations where fire-rated glass can be used, as well as the test standards the glass must meet to be allowed. As architects learn about the options they realize that they can use special glass in locations perviously limited to opaque materials. This helps them open up the space visually, enhance daylighting, and provide better security visibility while maintaining the full fire safety required.
Fire-rated glass helps architects realize their vision in locations with technical fire requirements.